1. Field of the Invention
This invention relates to a process for the preparation of chlorofluorocarbons and to a novel composition 2,2-dichloro-1,1,1,3,3-pentafluoropropane.
2. Background
For modern technological advances, particularly in the electric field, utmost cleanliness of the electronic components has become an important and necessary requirement. For example, in the manufacture of modern electronic circuit boards with increased circuitry and component densities, thorough and effective cleaning of the boards after soldering is of primary importance. Cleaning of electronic circuit boards is presently done for the most part by solvent washing utilizing various solvents and processes.
The solvent of choice at the present time is 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) because this solvent provides the necessary characteristics required of an effective solvent such as convenient atmospheric boiling point, non-flammability, low toxicity, inertness to various materials of construction, high stability and high solvency. CFC-113 is often used with small amounts of co-solvent such as acetone or methanol to enhance certain solvency characteristics. CFC-113 and CFC-113-based solvents are also extensively used in cleaning of precision machine parts. In recent years, however, CFC-113 has been suspected of contributing to the depletion of the stratospheric ozone layer. Because of its unusually high stability, it is believed that CFC-113 remains intact in the earth's atmosphere until it reaches the stratosphere and there undergoes decomposition, the decomposition product bringing about the destruction of the ozone layer.
It is, therefore, obvious that there is an urgent need in the industry for a solvent to replace CFC-113 which will provide the beneficial solvent characteristics of CFC-113, but at the same time have little or no stratospheric ozone depletion potential.
It is an object of the present invention to provide an effective chlorofluorocarbon solvent system. It is a further object of the invention to provide an effective chlorofluorocarbon solvent system which has little or no effect upon the stratospheric ozone layer. It is still a further object of the present invention to provide an improved process for the manufacture of chlorofluoropropanes.